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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 116 |
| 5 | 2126 |
| 6 | 54132 |
| 7 | 1753074 |
| 8 | 69159400 |
| 9 | 3220837534 |
| 10 | 173103115760 |
| 11 | 10551652603526 |
| 12 | 719578430426044 |
| 13 | 54297978110913252 |
| 14 | 4492502634679508204 |
| 15 | 404469190271900056316 |
| 16 | 39370123445405248353744 |
| 17 | 4120204305690280446004838 |
| 18 | 461365717080849798202175772 |
[1,1,2,10,116,2126,54132,1753074,69159400, 3220837534,173103115760,10551652603526, 719578430426044,54297978110913252, 4492502634679508204,404469190271900056316, 39370123445405248353744,4120204305690280446004838, 461365717080849798202175772] |